Projection instrument.



G. B. BOYLE, DEGD. E. I & 2. M. BOYLE, ADMINISTRATRIOES PROJECTION INSTRUMENT.

APPLIOATION FILED 001 11, 1912.

Patented Feb. 3, 1914.

ATTORNE mm CL 8 8 M .I I W UNITED STATES PATENT OFFICE.

cnmns BARRY norm, moment, it Larva a. norm AND aorta u. some, ADMIN- assrenons, BY mnsnn ASSIGNMENTS, 'ro

nouns senescence, INCORPORATED, A conroan'rron or NEW YGRK.

Specification of Letters Patent. Application filed October 11, 1912. Serial 1%. 725,186.

Patented Feb. 3, 1914.

aflected by the extreme heat, sometimes even being cracked or shattered.

This invention is adapted to concentrate light emanating rom a suitable source and bring it to a focus substantially as would be done by the ordinary condenser.

One form of the improvement is hereinafter described, and is illustrated in the accompanying drawlngs forming a part of this specification, in which- F' ure 1 is a front view of the instrument and ig. 2 a vertical section on the line 22 of Fig. 1, and is intended to represent the instrument 'inposition in the condenser cell of a kinematograph or other projection instrument.

Referri to the drawings, A represents an ellipsoi al reflector of suitable diameter and len h and preferably end so t at the light C may be placed atthe focus. The reflecting surface of A is concentric with the major axis of the generating ellipse, the foci, ofwhich may be spaced apart as required for any particular instrument so that the source of light C will be at one focus while the converging rays of reflected light will be concentrated at a focus located at the optical center of the objective. It is impractical to have the large ellipsoidal reflector A very long, hence as indicated in Fig. 2 it is usually only a fractional part of the length of the major axis of the generating ellipse. This length in the present instance is adapted to receive and reflect all rays of light between the cones indicated by of Fi 2, which are reflected toward the other Iocus along the lines 1 and 2 This length, however, is not suflicient to intercept the cone of divergent rays between the lines the invention is to provide open at the small the dotted lines 1 and 2- 2, which, it will be seen, would pass beyond the forward end of the reflector A. In the form of the invention here shown the divergent rays between the lines 2 which, as stated, would escape the reflector A are preferably collected and caused to converge at the same oint by another member comprising a den le ellipsoidal reflector B of hourglass shape located within and concentrically of the axis of the reflector A. The pos terior section B of the reflector B flares out toward the source of light and is a portion of such an ellipsoid as would be generated by an ellipse having one focus at the source of light C'and the other at the point J.

The flaring end of the reflector B as will be seen from Fig. 2, is so located as to receive all the diverging rays of light in the cone between the otted lines 2 and reflect them to and through the focus J. The small end of the reflector B is preferably removed as shown at B in a plane passin through the focus J and is united in this p ane with the smaller end of the forwardly flaring ellipsoidal reflector B The ellipsoidal refleet-or B has its end removed along the plane B which, as with'B", passes through its focus thus making the point 3 the focus of both reflectors B and B hence all rays of light reflected from B after passing through the focus J will be received and reflected from the surface of B and caused to converge toward the other focus of the elli'psoid, which in the present instance coincides with the focus K. v

The double ellipsoidal reflector member B is arranged in the mouth of the large reflector A concentrically with the axis thereof and may protrude therefrom if convenient or desirable, the arrangement being such that the combined focal lengths of the generating ellipses of the reflectors B and 13 shall equal the focal length of the generating ellipse of the reflector A. In other words the rays of light gathered from the diverging cone between the dotted lines 2 by the reflector B will be brought to the optical center K of the objective along with the converging rays between the lines 1 and 2'- coming from the reflector A, as previously explained. Thus practically all the light emanating from-the source of light 0 and diverging therefrom within the cone determine by the circular small end of the reflector A indicated by the dotted lines 1) will be re ected by the compound condensing reflector. comprising theellipsoidal reflectors A, B and B and brought to the same focus K, which in the resent instance is the optical center of the o jective or projecting lenses D and E. It will thus be seen that the invention may be substituted for the usual condenser lens in projecting lanterns or the like, the front board of such an instrument being indicated at H in Fig. 2 and the condenser tube or cell at G.

The ellipsoidal reflector A and the members of the double ellipsoidal reflector B may be calculated either conjointly or separately for any desired the respective reflectors being determlned by the size of the instrument and the relative position of the light and the projection lens. In adapting or substituting this invention for the ordinary condensing lens, the requirements are the same, that is, for any particular instrument the cone of divergent rays from the source of light must be collected by the condenser and caused to converge toward a focus located at the optical center of the projection lens.

The invention is not limited to the particular form or arrangement shown for it and it will be readily understood that various modifications maybe made in adapting the device to various instruments without departing from the spirit and scope of the claims.

What is claimed is:

1. A compound condensing reflector comprising a plurality of concentrically arranged ellipsoidal reflectors adapted to change divergent rays from a source of light to rays convergent to a common focus, the inner ellipsoidal reflectors being of such focal length that the combined focal length of two of them placed end to end shall equal the focal length of the outermost reflector.

2. A condensing reflector comprising two frustums' of ellipsoidal reflectors, cut off in planes parallel to the revolving axis and placed in axial alinement with the small ends of said frustums united so that adjacent foci are coincident, the arrangement being such that divergent rays of light from the outer focus of one frustum will be condensed at the outer focus of the other frustum.

3. A compound condensing reflector comprising an outer ellipsoidal reflector of given focal length, anda pair of ellipsoidal reflectors placed end to end and axially within said outer reflector, the combined focal length of the end to and inner reflectors being equal to the given focal length of the outer reflector, .whereby divergent rays of light emanating from one focus of the compound reflector will be intercepted and reflected conjointly by the several reflectors focus; the focus of cut away in a plane perpendicular Ltetniet and caused to converge toward the other focus thereof.

4. The combination of a source of light, a projection lens, an ellipsoidal reflector, two smaller ellipsoidal reflectors which are cut away in a plane perpendicular to their major axes, approximately attheir foci and placed back to back and which are located within the larger reflector in such a position as to intercept divergent rays and direct them outwardly in convergent beams, the larger ellipsoidal reflector and the-two smaller ellipsoidal reflectors being so constructed and arranged that the focus of the cone of rays sent forward conjointly by both members of the reflecting system shall lie at substantially the focus of the lens system.

5. The combination of a source of light, a projection lens, and a compound ellipsoidal reflector the ellipsoidal members of which are so calculated and arran ed that divergent rays from the soure 0 light reflected therefrom will converge to a common focus at the optical center of said projection lens.

6. The combination of a source of light, a projection lens and a condensin reflector comprising an outer ellipsoidal re ector and two smaller ellipsoidal reflectors which are to their major axes, approximately at their foci and placed back to back, the two reflectors being located axially within said outer member in such position as to receive and reflect di-- vergent rays which would otherwise escape beyond the forward end of said outer reflector, the several ellipsoidal members bein so constructed and arranged that the cone of convergent rays sent forward by the reflector as a whole will be brought to a focus at substantially the optical center of the projection lens. Y

7. The combination of a source of light, a projection lens and a reflector-condenser comprising an outer ellipsoidal reflector having a focal length equal to the distance between the source of H ht and the optical center of said lens, and two smaller ellipsoidal reflectors placed end to end and axially within saidouter reflector, the combined focal length of the end to end small reflectors being equal to the focal len th of said outer member, the arrangement ein such that divergent rays from the source 0 light,

intercepted by said ellipsoidal reflectors, will I be brought to a common focus at the optical center of said lens. I

8. The combination of a source of light, a projection lens and a reflector-condenser comprising an outer ellipsoidalreflector and two smaller ellipsoidal reflectors placed end to end with their foci coinciding, and so located axially within said outer reflector that the flaring end of one reflector will be toward the source of light and at such a distance therefrom as to intercept the cone of rays which would otherwise escape reflection from said outer reflector, the arrangement being such that the intercepted divergent rays are reflected from the several ellipsoidal reflectors and ultimately brought -to a common focus at the optical center of said lens.

9. The combination of a source of light, a projection lens and a pair of ellipsoidal reflectors placed in axial alinement with adjacent foci coincident, the other foci being at the source of light and at the optical center of said lens respectively.

10. The combination of a source of light, a projection lens and a pair of ellipsoidal reflectors which are cut away in a plane perpendicular to their major axes, approximately at their foci and placed back to back, one reflector having its outer focus at the source of light andadapted to receive divergent rays therefrom and the other reflector having its outer focus at the optical center of said lens thereby being adapted to reflect light received from the first reflector and converge it toward the focus at said optical center. i

11. The combination of a source of light, a projection lens and a reflector condenser comprising an ellipsoidal reflector interposed between said source of light and said projection lens and havinga focal length equal to the distance between the source of light and the optical center of said lens whereby all divergent rays emanating from said source of light and striking said reflector are concentrated at the optical center of said lens.

Signed at the city county and State of New of October, 1912.

ELVA J. BOYLE, ZOLA M. BOYLE, Administratrices of Gharles Barry Boyle,

deceased. Witnesses:

A. C. MCDONNELL, S. J. Cox.

of New York, in the York, this 4th day 

